Allison Transmission Holdings Inc. and Cummins Inc. said they have received certification from the California Air Resources Board (CARB) for model year 2019 Allison Hybrid 40/50 electric propulsion (H 40/50 EP) system paired with the Cummins B6.7 and L9 diesel-electric hybrid engines, used in transit buses and coaches.
Originally issued by the CARB in 2014, the dual executive order is required to be reviewed for renewed eligibility on a model year basis. The paired Allison electric hybrid-propulsion system and Cummins engine is used in both straight and articulated transit buses.
The Cummins B6.7 and L9 diesel-electric hybrid engines were developed in-house. The B6.7 diesel-electric hybrid engine is rated at 280 hp (209 kW) while the L9 diesel-electric hybrid engine is rated at 330 hp (246 kW) for the transit bus market.
Allison said the H 40/50 EP has been proven to improve fuel economy up to 25 percent. Additionally, its regenerative braking capability can significantly extend the brake change interval by as much as 350 percent.